The research outlined in this proposal deals with several aspects of biologically active compounds produced by microorganisms. The main emphasis is on the biosynthesis of a number of antibiotics. The methods to be used include feeding experiments with precursors labeled with radioactive isotopes, but also to a large extent the use of 13C-labeled compounds in conjunction with 13C Fourier Transform NMR. Antibiotics to be investigated are pyrrolnitrin, chlorothricin, boromycin, granaticin, the naphthocyclinones, dihydrophenylalanine, ketomycin and anticapsin. In addition some structural work is proposed which involves the isolation and structure elucidation of some new naphthoquinone-type compounds found in the cultures of the granaticin-producing organism. Also within this project, some pilot studies will be carried out to explore possibilities of biotransformation of antitumor antibiotics. Also in collaboration with some synthetic organic chemists engaged in total synthesis of natural products and analogs we will evaluate their synthetic ccmpounds for biological activity and/or help them establish identity of the synthetic and the natural material.